BJCP Guidelines – BJCP lists specific style guidelines for beer, which is updated every so often. Guidelines are defined in very specific terms, including original and final gravities, color and bitterness, and overall flavor and aromas the beer should have.

Brettanomyces – A genus of yeast. Brett encompasses “wild yeast”, and imparts acidic, funky, and/or strong fruity flavors into beer. Used mostly in the production of Belgian sours, Brett has also been more recently used for American wild and sour beers.

Brix – A measure of percentage sugar content by weight. Commonly used by winemakers. Calibrated to 68°F

Campden Tablet – Tablet form of Potassium or Sodium metabisulfite. Used in brewing water to reduce chloromine.

Chill Haze – Haze in finished beer caused by an abundance of proteins or hop oils.

Chlorine – A common disinfectant used in municipal drinking water to keep it from spoiling. If used for brewing, will interact with yeast during fermentation to create harsh, soapy flavors. Can be removed by boiling water. Has fallen out of favor in recent years, in favor or chloromine.

Chloromine – A more stable form of chlorine used to disinfect drinking water. Cannot be boiled away, but can be broken down with a campden tablet. 1 campden tablet will dechlorinate up to 10 gallons of water.

Clarifiers – Additives added towards the end of the boil to aid in clarification by coagulating proteins. Options include Irish Moss and Whirlfloc.

Cold-Crashing – The process of cooling down beer after fermentation. This helps particulates settle out of suspension, and aids in clarifying and racking beer.

Diacetyl – A chemical compound that gives a distinctive butter or butterscotch flavor. Commonly seen as an off-flavor, especially in lagers, it can be acceptable in small amounts in English or Scotch ales. Produced by most yeasts during fermentation, and broken after fermentation.

Diastatic Power – Refers to the amount of enzymes readily available to convert starches into fermentable sugars.

DMS – Dimethyl Sulfide, a compound made from the boiling of wort. If allowed to condense back into the wort, will show as an off-flavor in the form of a strong cooked corn flavor.

Enzyme – A chemical compound that causes specific reactions. In beermaking, enzymes within malt break down starches into fermentable and unfermentable sugars.

Finings – Additives added to beer after fermentation to aid in clarification by aiding in yeast flocculation. Options include Isinglass, Gelatin, Super Kleer, as well as others.

Flocculation – The process of yeast dropping out of suspension towards the end of fermentation. Different yeasts have different levels of flocculation; high flocculating yeasts drop out of suspension much more readily than low flocculating yeasts.

Gravity – A measure of density of liquids. Sugar and other dissolved solids increase density. Commonly used by homebrewers to talk about sugar contents, both before and after fermentation.

Hops – The flower of the humulus lupulis plant. Added to beer at various stages to impart bittering, flavor, and aroma components to beer.

Hops Spider – A stainless steel holder, sometimes with a stainless mesh or made for use with a nylon straining bag, made to go into a brew kettle. Hops are added into the mesh or bag to aid in removing them post boil.

Hybrid Beer – And beer style that does not fall into standard yeast paradigms. Can be a beer with a lager yeast fermented warm at ale temperatures, or a beer with an ale yeast fermented at cold lager temperatures.

Hydrometer – A tool used to measure density of a liquid. Commonly sold as triple-scale hydrometers which read gravity, brix/balling, and potential alcohol, used in beer and wine making.

Hydrometer Jar – Any long, skinny tube that is filled with wort or beer and floated with a hydrometer.

IBUS – International Bitterness Units, a common measurement used to identify bitterness of a beer.

Krausen – The frothy, foamy buildup of yeast during active fermentation. Can last anywhere from 2-7 days typically.

Lactobacillus – One of two main souring bacteria used in sour beer making. Will primarily produce lactic acid. A slow fermenter, Lactobacillus requires a minimum of 3 months in secondary.

Lager – Any beer fermented with a lager yeast at lager temperatures. Lager is German for storage, and refers to how these beers were originally made.

Lag time – The time between pitching yeast into wort and seeing visible, active signs of fermentation. Can last anywhere from 6 hours to 2 days typically.

Lauter – The filtering or separating of grains after the mash.

Lauter tun – The vessel in which the lauter is performed. Typically will contain a filter medium, such as a false bottom, attached to a valve on the bottom, allowing clear wort to be drained, leaving grains behind.

Lovibond – A degree measure of color used for malts and grains. Higher degrees correlate to a darker malt.

Malt – Any grain that has undergone malting, the process of partially sprouting grain to ready enzymes for the conversion of starches to sugars.

Malt Extract – Malt that has been mashed, then had water content partially removed to concentrate malt sugars. Comes in a variety of forms:

DME – Dried malt extract, a powdered form of malt extract. Contains high sugar content and a long shelf life.

LME – Liquid malt extract, a thick syrupy form of malt extract. High sugar content (though not as high, by weight, as DME), and a slightly shorter shelf life. Much easier to dissolve in water.

HME – Hopped malt extract. Usually sold as a canned kit. Usually the kit is simply dissolved in water, then transferred into a fermenter and fermented. Typically will not make excellent quality beers.

Mash – The process of converting starches to sugars in malt, using enzymes within the malt. Involves soaking the malt in a specific amount of hot water at a specific temperature, usually for an hour.

Mash tun – The vessel in which the mash is performed. Often mash and lauter tuns will be the same thing for homebrewers, collectively called a mash lauter tun, or MLT.

Over-pitching – Pitching too much yeast into wort. Will cause an off-flavor in the form of a very clean profile, related to insufficient budding of yeast during the first phase of fermentation. Specific rates of over-pitching are not precise, and in general it is much more difficult to over-pitch than it is to under-pitch.

Pediococcus – One of two main souring bacteria used in sour beer making. Will primarily produce lactic acid, but can also produce diacetyl and increase viscosity of the beer. Viscosity will be broken down over time by Brettanomyces.

Pitching rate – The specific amount of yeast added to wort for fermentation.

Plato – A measure of percentage sugar by weight in solution, similar to brix and balling. Commonly used by commercial brewers.

Priming solution – A solution of sugar in water, added to beer for bottle conditioniong.

Racking/Siphoning – The act of transferring wort, beer, or other liquids from one vessel to another, using gravity. A racking cane or auto-siphon is placed in the beer, the vessel is placed above the secondary fermenter, keg, or bottling bucket, and tubing is attached to the racking cane and place in the lower vessel, and the siphon is then started.

Refractometer – A tool used to measure gravity or brix. Uses a couple drops of liquid, which is placed on the front screen, and held up to the light. Excellent for pre-fermentation readings, large corrections needed for post-fermentation readings.

SRM – Standard Reference Method; one of several systems of measuring beer color. Involves measuring light as it passes through finished beer. Commonly used by American commercial brewers and homebrewers.